1. Field of the Invention
The present invention relates to a continuously variable transmission apparatus and an air conditioning system having the same.
2. Description of Related Art
Japanese Unexamined Patent Publication No. S61-140664A teaches a continuously variable transmission apparatus, which can adjust an input-to-output speed ratio between an input rotational speed and an output rotational speed of the continuously variable transmission apparatus by changing the amount of eccentricity of an eccentric cam arrangement. In this continuously variable transmission apparatus, the eccentric cam arrangement, which has the variable amount of eccentricity relative to an input shaft, is provided to rotate integrally with the input shaft, and a plurality of crankshafts is rotatably placed one after another along an imaginary circle, which is coaxial with the input shaft. An end part of each crankshaft is slidably received in a corresponding cam groove of the eccentric cam arrangement. Furthermore, a plurality of planetary gears is provided such that each planetary gear is connected to the corresponding crankshaft through a corresponding one-way clutch and is meshed with a ring gear, which is connected to an output shaft to rotate the same.
The eccentric cam arrangement includes an inner eccentric cam and an outer eccentric cam. The inner eccentric cam is fixed to the input shaft, and the outer eccentric cam is rotatable relative to the input shaft. Specifically, the outer eccentric cam is connected a differential gear, the planetary gears, a worm wheel, a worm and a handle. When the handle is rotated, the outer eccentric cam is rotated relative to the inner eccentric cam. In this way, the amount of eccentricity of the eccentric cam arrangement, which is rotated integrally with the input shaft, relative to the input shaft is adjusted.
With the above structure, when the amount of eccentricity of the eccentric cam arrangement relative to the input shaft becomes small, the input-to-output speed ratio becomes small. In contrast, when the amount of eccentricity of the eccentric cam arrangement relative to the input shaft becomes large, the input-to-output speed ratio becomes large. Thereby, the input-to-output speed ratio can be adjusted linearly (continuously, i.e., steplessly).
However, in the above continuously variable transmission apparatus, when the input-to-output speed ratio is adjusted, the amount of eccentricity of the eccentric cam arrangement, which is rotated integrally with the input shaft, is changed. Therefore, a rotational balance disadvantageously varies from one input-to-output speed ratio to another input-to-output speed ratio. Furthermore, the differential gear, the planetary gears, the worm wheel, the worm, and the handle are provided to adjust the amount of eccentricity of the eccentric cam arrangement, which is rotated integrally with the input shaft, relative to the input shaft. Therefore, the number of the components is disadvantageously increased, resulting in an increased complexity of the structure.
Japanese Patent 3738535B2 (corresponding to U.S. Pat. No. 6,171,210B2) recites another continuously variable transmission apparatus that includes a continuously variable transmission mechanism, i.e., a variator and implements an improved durability of the continuously variable transmission apparatus by reducing a load of the continuously variable transmission mechanism.
Specifically, the continuously variable transmission apparatus includes a first power transmission mechanism and a second power transmission mechanism. The first power transmission mechanism circulates a drive force (power) of a planetary gear mechanism to the variator. The second power transmission mechanism conducts rotation of input disks of the variator to the planetary gear mechanism while bypassing power rollers and output disks of the variator.
The second power transmission mechanism includes a bypass shaft, which conducts the drive force. This bypass shaft is parallel to the input shaft and the output shaft of the variator and is non-coaxial with the input shaft and the output shaft of the variator.
According to the prior art technique of Japanese Patent 3738535B2 (corresponding to U.S. Pat. No. 6,171,210B2), since the second power transmission mechanism, which bypasses the power rollers and the output disks of the variator, is placed in the power transmission path, the load of the variator is reduced, and thereby the durability of the continuously variable transmission apparatus can be improved.
However, in the prior art technique of Japanese Patent 3738535B2 (corresponding to U.S. Pat. No. 6,171,210B2), the drive force of the planetary gear mechanism is circulated to the variator through the first power transmission mechanism. Therefore, the length of the power transmission path is increased to cause an increase in a mechanical loss (causing a reduction in efficiency).
Furthermore, in the prior art technique of Japanese Patent 3738535B2 (corresponding to U.S. Pat. No. 6,171,210B2), the bypass shaft of the second power transmission mechanism is non-coaxial with the input shaft and the output shaft. Therefore, an entire size of the continuously variable transmission apparatus is disadvantageously increased in a radial direction of the input shaft and the output shaft.